We included a total of 99 studies that reported empirical data about 22,766 people with SARS-CoV-2 infection (8,103 defined as having asymptomatic infection), 8 studies for Q2.1, and 22 studies for Q2.2.

We included 99 studies that reported empirical data about 22,766 people with SARS-CoV-2 infection (8,103 defined as having asymptomatic infection) (Table 1).

<<<<<<< HEAD Figure 1. Forest plot of proportion of people with asymptomatic SARS-CoV-2 infection, stratified by setting and ordered by precision ======= >>>>>>> e643a5888e1f23760c6f4a2efc2c474f9e910b81

Figure 1. Forest plot of proportion of people with asymptomatic SARS-CoV-2 infection, stratified by setting and ordered by precision

The main risks of bias across all categories of empirical studies were in the selection and enrolment of people with asymptomatic infection and mismeasurement of asymptomatic status because of absent or incomplete definitions (S3 Fig). Sources of bias specific to studies in particular settings are discussed with the relevant results.

Figure 2.1. Forest plot of secondary attack rate comparing infections in contacts of asymptomatic and presymptomatic index cases with infections in contacts of symptomatic cases, ordered by precision

Figure 2.1. Forest plot of secondary attack rate comparing infections in contacts of asymptomatic and presymptomatic index cases with infections in contacts of symptomatic cases, ordered by precision

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Figure 4. Forest plot of proportion of SARS-CoV-2 infection resulting from asymptomatic or presymptomatic transmission

Figure 4. Forest plot of proportion of SARS-CoV-2 infection resulting from asymptomatic or presymptomatic transmission